The invention relates to compositions for controlling Varroa mite infestation in bees.
Honey bees, Apis mellifera, are required for the effective pollination of crops and are therefore critical to world agriculture. Honey bees also produce economically important products, including honey and bees wax. Honey bees are susceptible to a number of parasites and pathogens, including the ectoparasitic mite, Varroa destructor.
Colony Collapse Disorder (CCD) of honeybees is threatening to annihilate U.S. and world agriculture. Indeed, in the recent outbreak of CCD in the U.S. in the winter of 2006-2007, an estimated 25% or more of the 2.4 million honeybee hives were lost because of CCD. An estimated 23% of beekeeping operations in the United States suffered from CCD over the winter of 2006-2007, affecting an average of 45% of the beekeepers operations. In the winter of 2007-2008, the CCD action group of the USDA-ARS estimated that a total of 36% of all hives from commercial operations were destroyed by CCD.
CCD is characterized by the rapid loss from a colony of its adult bee population, with dead adult bees usually found at a distance from the colony. At the final stages of collapse, a queen is attended only by a few newly emerged adult bees. Collapsed colonies often have considerable capped brood and food reserves. The phenomenon of CCD was first reported in 2006; however, beekeepers noted unique colony declines consistent with CCD as early as 2004. Various factors such as mites and infectious agents, weather patterns, electromagnetic (cellular antennas) radiation, pesticides, poor nutrition and stress have been postulated as causes. To date, control of CCD has focused on Varroa mite control, sanitation and removal of affected hives, treating for opportunistic infections (such as Nosema) and improved nutrition. No effective preventative measures have been developed to date.
Varroa mites parasitize pupae and adult bees and reproduce in the pupal brood cells. The mites use their mouths to puncture the exoskeleton and feed on the bee's hemolymph. These wound sites in the exoskeleton harbor bacterial infections, such as Melissococcus pluton, which causes European foulbrood. In addition, to their parasitic effects, Varroa mites are suspected of acting as vectors for a number of honey bee pathogens, including deformed wing virus (DWV), Kashmir bee virus (KBV), acute bee paralysis virus (ABPV) and black queen cell virus (BQCV), and may weaken the immune systems of their hosts, leaving them vulnerable to infections. If left untreated Varroa infestations typically result in colony-level mortality.
Current methods of treating Varroa infestations are proving to be ineffective as the mites develop resistance to existing miticides. In addition, the use of such miticides may introduce injurious chemicals into honey that is intended for human consumption.
U.S. Patent Application 20090118214 teaches the use of dsRNA for prevention and treatment of viral infections in honeybees.